This invention relates to devices for the fastening of a railroad rail to a crosstie or sleeper and, more specifically, relates to devices for permitting the refastening of a railroad rail to a crosstie using an existing spike hole in a crosstie after extended use thereof.
The modern railroad rail has a flat bottom and its cross-section is much like an inverted T. The rails are fastened in pairs, in a spaced apart and parallel relationship to sleepers or crossties with spikes of steel. While historically, the cross sections of rails have varied greatly, there is a strong movement today to standardize both the length and weight of the rail. An accepted length is about 39 feet with a weight of about 136 pounds. Rails are typically laid in lengths and joined end to end by fishplates or joint bars. The rails may be fastened directly to the crossties but it is generally preferred, particularly in heavy traffic areas, to use a tie plate that seats a rail such that the weight is distributed over a greater area of the crosstie. The preferred fastener is the off-set head spike although there are other fasteners at higher cost that may be used.
The cross ties have been traditionally wood treated with a preservative chemical to extend the life of the crosstie which may approach 35 years. The rising cost of wood has made the concrete crosstie more economically attractive but wood still remains by far the preferred material. One of the more important developments in railroad track has been the use of welded rail sometimes as long as 1/4 mile. Temperature expansion has not been as large a problem as thought. Control of the expansion is accomplished in part by extensive anchoring of the rail to the crosstie through use of heavy ballast to prevent the rail from moving.
The tracks are laid down in parallel with the distance between the inner faces of the parallel rails being called gage. It is important that this gage be maintained with some exactness since too large a gage causes vibration and rough riding and in the most severe conditions leads to disrailment. Because of the continuous force being exerted outwardly by the wheels of trains using a track, a significant force is exerted periodically against the crossties by the railroad spikes away from the centerline of the track formed by the rails. This periodic force causes the hole made by the spike when driven into the tie to become progressively larger, particularly accentuated at the top of the opening of the hole. Left unattended, the spikes will tend to retrograde out of the hole and/or lean into the widening hole under pressure of a train moving over the rails thereby widening the gage of the track beyond acceptable limits.
Many attempts have been made to solve the problems of spike retrograde and gage change of railroad tracks. Complicated, and consequently much more expensive, spike structures have been offered to provide increased anchorage into the wood of the crossties and to prevent retrograde movement of the spike and minimize the effect of the hole widening. A very earlier attempt is illustrated by U.S. Pat. No. 977,795 which uses an off-set spike having an elongated central cavity running the length thereof adapted to receive a removable pin. Once the spike is pounded into the tie, the pin is then forced into the cavity and causes a pair of teethed members to pivot out of the body of the spike into the surrounding wood of the crosstie. The spike cannot move since it is anchored by the pivoting members against retrograde movement. Variations of this type of spike can be found in U.S. Pat. Nos. 1,035,419, 1,113,947, and 3,865,307. Such spikes, however, have not proved to be commercially attractive due to the significant manufacturing costs.
Other attempts have been made using an insert which is driven into the hole along with the spike. The insert is typically expandable or provided with a series of spikes that prevent the insert and spike from moving out of the hole. Examples of the insert solution to the problem are found in U.S. Pat. Nos. 1,294,778, 1,774,968, 3,964,680, and 4,203,193. While the inserts may address the retrograde movement of the spikes, the widening gage problem remains a serious consideration.
The problem of widening gage has been largely addressed by removing the crosstie, replugging the hole, repositioning the rails to the proper gage, and then driving a spike into the crosstie. If the gage widening is significant, the entire crosstie is discarded. Clearly neither technique is desirable as both are costly. Moreover, discarding crossties before the life expectancy of the wood is reached is an environmentally unsound technique unless the crossties can be used for other and different purposes.
Thus, it is a paramount object of the present invention to provide for a device that permits gage of a track to be restored to its proper value after a period of use while reusing the crossties. It is another important object of the present invention to provide for a device permitting the use of a crosstie for a period of time approximating its normal wear life at a cost which is less than the replacement of the crosstie with a new one.
These and other objects will become readily apparent upon a reading of the description herein with the appended drawings.